Race to the Bottom of the Sea

When tragedy strikes and budding inventor Fidelia Quail is kidnapped, she faces her greatest challenge yet. The infamous pirate Merrick the Monstrous demands that she rescue his most precious piece of treasure, lost on the ocean floor. With the navy hot on their heels, Fidelia realizes that something other than black-hearted greed is driving Merrick. Can she piece together the mystery and master the perils of the sea before it's too late?